St. Luke’s Health System and its medical operations took in about $1.45 billion and spent about $1.37 billion in 2011, underscoring its growth as Idaho’s single largest health care provider.

St. Luke’s added a hospital in McCall and several physician practices. The acquisitions helped push its income and spending higher during the fiscal year spanning part of 2010 and 2011. They also added significantly to the system’s workforce, which has passed 10,000.

The system’s largest unit — St. Luke’s Regional Medical Center, which encompasses the hospitals and clinics in the Treasure Valley — has nearly tripled its revenue and doubled its employees since 2002.

The data come from St. Luke’s tax returns, which are public because the hospital system is a nonprofit that does not pay certain taxes, such as property or corporate income taxes. St. Luke’s has not filed a return for its most recent fiscal year, which ended two months ago.

It is not clear from the tax filings how much of St. Luke’s growth is from acquisitions and how much is from new patients, more services or higher prices.

In comparison, Saint Alphonsus Health System’s medical operations reported income of $689 million, spending of $669 million and about 5,300 employees in its latest tax filing. Saint Alphonsus’ Boise- and Nampa-area operations made up most of that.

EMPLOYEE PAY

St. Luke’s in the Treasure Valley spent 47 percent of its revenue on compensation and benefits for its 7,601 employees. That included $3 million for executives and key employees. The five highest-paid physicians earned a combined $4.9 million.

TAX BREAKS, CHARITY

St. Luke’s gets a break on taxes as a trade-off for taking patients who can’t pay. It must report how much unpaid and under-reimbursed care it provided, the discounts it gave and how many free services it provided. Those categories made up about 8.8 percent of spending by St. Luke’s Regional Medical Center. That included $34 million of unreimbursed medical care to low-income people and $35 million in research, cash grants to community groups, community health improvement services and other work.

St. Luke’s Regional Medical Center also reported a $45 million loss on its Medicare patients, after payments of $113 million. It also ate about $32 million that patients didn’t pay.

NONMEDICAL SPENDING

St. Luke’s in the Treasure Valley spent $2.7 million on advertising and promotion. The Regional Medical Center spent close to $1 million on architectural services.

Audrey Dutton: 377-6448, Twitter: @IDS_Audrey